多注耦合腔行波管互作用均匀性研究

对多注行波管慢波结构的特性进行了模拟与分析,利用粒子模拟方法,定量模拟了多注行波管的PIC注波互作用过程,通过比较不同电子注位置情况下电场E的振幅、相移、非线性和互作用效率,研究了多注电子注波互作用的均匀性特点,发现电子注位置不同时对电场有不同的影响,这对实际多注耦合腔行波管设计有一定指导意义。     

双槽型耦合腔行波管非线性注波互作用计算方法

建立了双槽型耦合腔行波管三维频域非线性注波互作用模型,推导出参与注波互作用电磁场及粒子运动方程组。根据模型与方程组编写非线性互作用计算程序,模拟注波互作用过程,得到输出功率、增益等性能参数。计算结果与X波段双槽型耦合腔行波管实测数据比较,以验证计算方法的准确性,并对互作用过程中的非线性现象进行分析,希望能够辅助行波管的设计。     

过渡段螺距渐变对相速跳变的螺旋线行波管电子效率的改善

通过注波互作用机理的定性讨论得到了过渡段螺距合理渐变能改善螺旋线行波管效率的初步结论,而由过渡段螺距改变前后的螺旋线行波管色散方程和工作方程的理论分析得出的数值计算结果与初步结论相一致,并得出了过渡段螺距恰当的渐变方式对改善相速跳变螺旋线行波管的边频效率起很大作用的重要结论。得出的结论对螺旋线慢波系统设计工作的进一步开展指明了一个方向。     

注-波互作用的时域PIC 数值模拟

针对螺旋线行波管的注-波互作用过程,依据等效线路模型和动力学方程,采用粒子模拟方法进行时域计算,并给出部分主要的数值求解结果。本文的仿真结果基本与现有软件的模拟结果一致,同时针对由于计算模型不同而产生的计算偏差,给出了深入的分析,为后续的研究工作奠定了重要的基础。     

遗传算法在螺旋线行波管优化中的应用

遗传算法是一种可以对包含多个连续变量的目标函数进行全局优化的算法。本文在一维频域理论互作用程序的基础上,采用遗传算法对螺旋线行波管的慢波结构进行了全局优化设计,提高了行波管的互作用效率。在单频点优化过程中,螺旋线分成三段的情况下,利用遗传算法优化了输出功率最大的最佳螺旋线长度,然后利用遗传算法对多段螺旋线问题进行了优化。为了满足带宽的要求,本文又利用高低端优化的方法对螺旋线行波管进行了带宽优化,得出了一组高效的满足带宽条件的螺旋线行波管慢波结构的制管参数。     

利用三维粒子软件计算螺旋线行波管的互作用和三阶互调

采用三维电磁软件CST粒子工作室模拟单信号输入时某Ku波段螺旋线行波管的互作用及双信号输入时该行波管的三阶互调。模拟计算时,采用理想电子注和均匀聚焦磁场,对衰减器采用分段处理,通过设置每段衰减器材料的损耗正切值来表征其衰减量。单信号输入互作用模拟计算结果与实测结果非常接近,通过模拟得到了行波管双信号输入时两个基波信号输出功率以及三阶互调（IM3）产物,并给出输出信号的快速傅立叶变化频谱。     

卷绕双梳齿行波管中注-波互作用的研究

本文利用CST 软件中的粒子工作室对采用卷绕双梳齿慢波结构的圆极化行波管中的注-波互作用情况进行了粒子模拟研究,观察了电子束的运动情况,同时得到了电压、电流、磁场和输入功率四个重要电气参数对输出功率的影响。研究结果为圆极化行波管的设计奠定了理论基础。     

耦合腔行波管大信号注波互作用研究与设计

行波管中注波互作用的特点是电子的速度调制、群聚及其与高频场的能量转换等过程沿整个慢波结构连续且同时进行,这是行波管可以在很宽频带内得到大输出功率的原因。在研究冷腔特性的基础上,使用三维PIC粒子模拟软件定量分析了耦合腔行波管的大信号注波互作用过程,完成了X波段连续波行波管的设计。设计参数:工作频率7.18.5GHz,带宽18%,最大输出功率3kW。     

螺旋线行波管的三维互作用仿真方法研究

采用了CST工作室套装TM电磁仿真软件对一个典型的Ku波段螺旋线行波管的电子枪、磁聚焦系统、慢波结构和注一波互作用的非线性过程进行了三维的静电场、静磁场、粒子跟踪、本征模、粒子模拟的仿真和分析,得到了该行波管电子枪导流系数、慢波结构冷测特性以及输出功率和增益等参数,仿真所得数据与实测数据相符,证明了三维数值仿真全管的可行性,为后期设计和优化奠定基础。     

螺旋线行波管的互作用瞬时现象分析

由于现有的互作用理论模型无法快速实时地研究瞬态导通现象并针对传输信号进行时频分析,适当改进了传统 L.Brillouin 模型螺旋线损耗部分的同时结合IBC 模型的集中衰减器与切断设置方法,建立了螺旋线行波管的时域非线性 互作用理论模型。在此基础上对一支行波管的瞬态导通过程进行粒子模拟(Particle-In-Cell,PIC)计算,通过针对互作用末端 瞬态导通时间内传输信号进行的详细时频分析可知,电子注的前端截面无法理想地规则调制是输出信号杂乱和输出功率 谱线异常等复杂瞬态现象产生的主要原因之一。     

Ka波段连续波500W螺旋线行波管研究

Ka波段螺旋线大功率行波管在大容量的通信系统中具有重要作用,本文介绍了目前大功率连续波螺旋线行波管的现状,对相关技术进行了分析。通过对高频结构的互作用分析、热分析、多级降压收集极等分析,设计了一个Ka波段连续波500 W行波管的螺旋线互作用结构,计算机模拟结果表明可以满足设计要求。     

双渐变技术减小 AM-PM转换系数的初步研究

行波管欠压工作能减小AM-PM转换系数。因此在行波管中加入一段工作于该状态的慢波线应能改善AM-PM转换特性。由此引出了所谓双渐变技术。 本文对该技术作了初步分析,实际制管证明了该技术不仅能提高电子效率,而且能改善AM-PM转换特性。并且还具有多电平工作、降压效果好等优点。本文还总结了一套小信号设计方法。     

Efficiency Enhancement Of Helix Traveling Wave Tube Based On εMulti-Objective Evolutionary Algorithm

A two-dimensional non-linear helix traveling wave tube (TWT) theory in frequency-domain is described in this article and the theory is integrated with ε Multi-Objective Evolutionary Algorithm(MOEA). The efficiency optimization of a helix TWT with phase taper has been done. The optimization results was verified by a three dimensional nonlinear model. The results show the feasibility and reliability of the optimization algorithm and the two-dimensional nonlinear theory. The integrated program can provide calculable parameters for the design of helix TWT. It can also accelerate development process and reduce test costs.     

Field Theory of Planar Helix Traveling-Wave Tube

A pair of unidirectionally conducting screens, conducting in different directions, constitute a planar helix. The planar helix is proposed as a slow-wave structure for application in a traveling-wave tube (TWT). Field theory is applied to analyze the behavior of the planar helix in the presence of a flat electron beans present between the two screens. Results indicate the presence of three modes, with one mode having a negative attenuation constant, as in the case of the usual helix-type TWT. Curves are shown for a typical proposed planar TWT. Also, the effect of beam current is indicated.     

A study on helix pitch tolerance impact on TWT small-signal gain

Traveling-wave tubes (TWTs) consist of several sections with different helix pitch to provide the required small-signal gain. An extensive study aiming to improve the comprehension of the effect of the helix pitch manufacturing tolerances on the TWT small-signal gain has been completed. The obtained results demonstrate the relevant impact on the TWT small-signal gain when the helix pitch deviates from its nominal value and allow devising a tuning procedure for the realized tubes.     

行波管电镀铜螺旋线高温处理后变色问题的实验分析

对行波管螺旋线电镀铜工艺进行了描述和分析,从实验上阐明了烧氢后螺旋线表面颜色变化的原因。实验分析表明,Ni-Cu合金化反应是导致颜色变化的主要原因,而合金化的结果使表面电导率、热导率大大降低,因此,电镀铜工艺不适合于行波管螺旋线的表面处理。在此基础上,对螺旋线镀铜工艺的其他技术方案进行了评述。     

Design of Tip Loss Profile on Support Rod for a Helix TWT

This paper describes the design of tip loss profile on support rod for a high gain, high efficiency helix TWT. The tip loss profile at sever ends for the input and the output section of the helix slow wave structure has been designed for return loss at severs ends better than -20 dB. The experimental results have been carried out in the input and the output section of the helix assemblies for the high gain helix TWT to find the return loss in the region of carbon coated tip loss on the support rods. The experimental result has been compared with the simulated performance for the return loss at the sever ends. The design of tip loss profile on the support rod for helix TWT has been carried out in real situation using Ansoft HFSS. A good agreement has been found in the simulated and experimental results.     

Design of a tapered helix for suppressing backward wave oscillations in MMW TWT’s

Backward wave oscillations are easy occurred in high power helix millimeter wave traveling wave tubes (MMW TWT’s), owing to larger ka value and higher operating voltage. The start current of backward wave is calculated for helix TWT in Ka band. It is shown that start current will increase by used a tapered helix. Backward wave oscillations can be suppressed in tube. The design method of the tapered helix is given in this paper.     

The Key Technology of Efficiency Enhancement for Traveling Wave Tubes in Millimeter Wave

The efficiency enhancement methods for helix and coupled cavity traveling wave tube (TWT) in millimeter wave (MMW) are described. The interaction efficiency has been reached 14.56% by dynamic velocity taper in Ka-band TWT. Efficiency improvement has been carried out by used copper helix for broadband MMW TWT. Owing to a ferruleless coupled cavity TWT used phase-adjusted taper, the interaction efficiency has been increased from 9.6 to 22.6%. Finally, enhancing collector efficiency used multistage depressed collectors is discussed in the paper. These concept and technology of the approach are very useful for tube designer.